Feature request: support more syntax types for highlighting

[neilhwatson]

The syntax highlighter is missing common types HCL (HashiCorp) and YAML (aren't we all YAML users today ;))

[preaction]

The built-in highlighter uses https://metacpan.org/pod/Syntax::Highlight::Engine::Kate, which has apparently been deprecated in favor of https://metacpan.org/pod/Syntax::Kamelon. Kamelon supports YAML, but not HCL. You could either add support the Syntax::Highlight::Engine::Kate, move the Statocles::Plugin::Highlight to Kamelon (and add HCL support there), or switch to a JavaScript-based highlighter (HighlightJS comes to mind, but it also does not support HCL).